cjoslyn@bingvaxu.cc.binghamton.edu (Cliff Joslyn) (02/02/90)
In article <523@massey.ac.nz> ARaman@massey.ac.nz (A.V. Raman) writes: >The fact that entropy can never be reversed imparts unidirectionality >to time. Strictly false: in "real", isolated thermodynamic systems thermodynamic entropy cannot decrease. The difference is crucial. -- O-------------------------------------------------------------------------> | Cliff Joslyn, Cybernetician at Large, cjoslyn@bingvaxu.cc.binghamton.edu | Systems Science, SUNY Binghamton, Box 1070, Binghamton NY 13901, USA V All the world is biscuit shaped. . .
ssingh@watserv1.waterloo.edu ($anjay "lock-on" $ingh - Indy Studies) (02/02/90)
In article <523@massey.ac.nz> ARaman@massey.ac.nz (A.V. Raman) writes: > > >Would the human brain be capable of finding out that time is in fact >flowing backwards? > I don't think so. It appears that if you have negative entropy, you cannot perceive the passage of time. Time may become meaningless because you could remember the future as well as the past. There would not appear to be any sort of cause and effect relationship possible, that would show time flowing in one direction or another. Again this is from OUR vantage point with our brains set up to see time as we do now. It might be different entirely if our minds were in a universe that had negative entropy. -- $anjay "lock-on" $ingh ssingh@watserv1.waterloo.edu "A modern-day warrior, mean mean stride, today's Tom Sawyer, mean mean pride." !being!mind!self!cogsci!AI!think!nerve!parallel!cybernetix!chaos!fractal!info!
stefan@hpbbi4.HP.COM (#Stefan Bachert) (02/02/90)
In your scenery every brain forgots permanently memories and knowledge. Since every brain never gets new information it never can get new knowledge. But another question would be if live would be developed in such a physics. I think yes but why should people cognize it as reversed time. Or with other words why do you think that 'our' time is running forward ? Stefan Bachert
hwajin@ganges.wrs.com (Hwa Jin Bae) (02/03/90)
In article <940@watserv1.waterloo.edu> ssingh@watserv1.waterloo.edu ($anjay "lock-on" $ingh - Indy Studies) writes:
Again this is from OUR vantage point with our brains set up to
see time as we do now. It might be different entirely if our
minds were in a universe that had negative entropy.
This is an important point that gets little attention in many discussions.
In a larger context, Steven Hawking's (and many others') insistence to
categorically assign meanings to everything from the point of the observer
seems "natural", which is not to say scientific. The concept of time-space
as known to man may have no meaning whatsoever to some gaseous-cloud-like
alien creatures with consciousness (whatever it means to have one) whose
censory devices cannot register the meaning of "unit" or "measurement" at all.
The negative entropy idea seems to take it for granted that the same type
of value references can remain in an entirely different time-spatial condition.
It's also not clear what he means by "entropy" here as he doesn't clarify
what he considers "entropy" or "negative-entropy". Claude Shannon was
knowned to have said that he was urged to use the word "entropy" in his
information theory by Von Neuman who asserted that he should use it because
no one really knows what it means.
hwajin
--
Hwa Jin Bae, Wind River Systems, Emeryville CA
hwajin@wrs.com (uunet!wrs!hwajin)ARaman@massey.ac.nz (A.V. Raman) (02/07/90)
In article <HWAJIN.90Feb2124037@ganges.wrs.com> hwajin@ganges.wrs.com (Hwa Jin Bae) writes: >It's also not clear what he means by "entropy" here as he doesn't clarify >what he considers "entropy" or "negative-entropy". Claude Shannon was >knowned to have said that he was urged to use the word "entropy" in his >information theory by Von Neuman who asserted that he should use it because >no one really knows what it means. By negative entropy, here, I meant the situation where every event in the universe, started reversing. This includes events in the sub-atomic scale as well as the macro-cosmic scale. Perhaps, as you say, the word `entropy' is a misfit here; but the idea was to convey the question that if time started reversing, would the human mind be capable of finding that out. Since what we think at any instant is determined by the structure of the brain at that instant, when time starts reversing suddenly, we would still think exactly what we thought during the period of `positive entropy' when we had that brain structure. As a result of which, we may never know whether `entropy' in the Universe is actually increasing or decreasing, only that our brains are oriented in the direction of `positive entropy'. &/..
gerry@zds-ux.UUCP (Gerry Gleason) (02/10/90)
In article <2895@bingvaxu.cc.binghamton.edu> cjoslyn@bingvaxu.cc.binghamton.edu.cc.binghamton.edu (Cliff Joslyn) writes: >In article <523@massey.ac.nz> ARaman@massey.ac.nz (A.V. Raman) writes: >>The fact that entropy can never be reversed imparts unidirectionality >>to time. >Strictly false: in "real", isolated thermodynamic systems thermodynamic >entropy cannot decrease. The difference is crucial. I hesitate to throw my two cents in on this subject since it seems a bit far from the central concerns of AI, but I think this is relavent. A little while back someone posted a review of Penrose' _The_Emporer's_New_ Mind_ on sci.nanotech, and then I posted an article contrasting this position to the one presented by Paul Davies in _Cosmic_Blueprint_. Davies spends quite a bit of time on the "arrow of time" issue, pointing out as Cliff does that the entropy arrow only applies to closed systems, and then it may not apply to the entire universe as a closed system, since it doesn't really handle clumping due to gravity (and maybe other things). He also explores the idea of a synthetic (my word) arrow of time as evidenced by the increasing levels of organization that have emerged over time. Arguments like the Chinese Room are essentially reductionist, and do not allow that properties can emerge in a whole system that is not present or even explainable from the individual components. If an artificially intelligent machine is designed and works, it would be just another example of an emergent phenomenon, perhaps parallel to the emergence of human intelligence, perhaps at a new level. These issues are very difficult to analyse, since their understanding usually requires much level crossing. QM seems to be dependent on conscious (or something) observers, QM has implications for cosmology, and these relate to the arrow of time also (wave function colapse appears to be non-reversable, so it blows the original poster's speculation out of the water entirely). As the measurements of the cosmic background get better, it's getting harder and harder to explain how the universe could be as lumpy as it is. The world is a strange and wonderful place, isn't it? Gerry Gleason
hwajin@wrs.wrs.com (Hwa Jin Bae) (02/10/90)
In article <538@massey.ac.nz> ARaman@massey.ac.nz (A.V. Raman) writes: >By negative entropy, here, I meant the situation where every event in the >universe, started reversing. This includes events in the sub-atomic scale >as well as the macro-cosmic scale. Perhaps, as you say, the word `entropy' >is a misfit here; but the idea was to convey the question that if time >started reversing, would the human mind be capable of finding that out. Entropy is definitely the wrong word to use here if that's the idea you're trying to convey. The classical/thermodynamic definition of the word entropy is a measure of the amount of energy no longer capable of conversion into work. The thermodynamics teaches us that the total energy of the universe is constant and the total entropy is continually increasing. By using the word entropy in your article about the matters of human perception in the event of time-flow reversal, the basis of your proposition is unnecessarily contaminated with the unsound thermodynamic background. -- hwajin@wrs.com (uunet!wrs!hwajin) "Omnibus ex nihil ducendis sufficit unum." Hwa Jin Bae, Wind River Systems, 1351 Ocean Avenue, Emeryville, CA 94606, USA